A Briton who has fought Islamic State forces in Syria says British jihadists who travel abroad to fight should not be allowed to return home because of the extreme threat they present.

Macer Gifford, 30, from Cambridge, gave up a career as a banker in London to join the Kurdish People's Protection Units (YPG) as a foreign volunteer. Here is his view:

As long as I live I will never be able to articulate, in person or on paper, how evil the Islamic State is. The savagery and cruelty of the ISIS death cult is only truly appreciated when viewed up close.

I can't tell you how I felt when I helped liberate an IS brothel, where girls as young as nine were kept chained to the ground. I wept when I realised it was empty. Hours earlier the girls had been packed into cars and driven south.

All I could do was walk hopelessly amongst the dirty mattresses and chains, praying that we'll find them soon.

Image:Mr Gifford says it is not the UK's responsibility to bring back British former IS fighters

We have all been exposed to the IS' vile propaganda. The group's ability to harness social media has been unprecedented.

No terror group in history has been able to reach directly into people's homes, spreading both fear and their twisted ideology.

IS spends millions of dollars and thinks very carefully about the new depths of depravity their propaganda can sink too.

The group has always been erratic but its message of hate has always been consistent. It's this consistent message that makes the IS foreign fighter - particularly those from the West - so incredibly dangerous.

These people have had every opportunity in life, they have grown up in places like Britain in both comfort and security.

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Video:British banker fighting IS in Syria

Despite the education and opportunity afforded to them, they have decided to abandon the West and pursue jihad in Syria.

They knew exactly what the Islamic State was, yet still decided to go.

Now these jihadist fighters are begging to return to Britain. Long gone is their arrogance as they burned their passports and planned horrible attacks on the UK.

They now claim to be disillusioned and deeply regretful. Let's be absolutely clear, had it not been for the collapse of IS these men and women would not be coming back.

They now face a stark choice, die a miserable death in Syria or try to return to Britain. Many are now choosing to play the system - after all, they know how difficult it is to prosecute them.

They should be arrested if they can somehow get to our borders or onto the British mainland. Other than that, these men and women should be left to their fate in the Middle East.

I have seen with my own eyes what these people have done and what they are capable of. It was their choice to pursue a life of violence and murder. It is not Britain's responsibility to bring them back.